1. Field of the Invention
The present invention relates generally to a color television receiver, and is directed more particularly to a color television receiver with an automatic phase control (APC) circuit.
2. Description of the Prior Art
In a prior art color demodulating circuit for use with a color television receiver, an APC circuit, employs a color burst signal derived from a color television signal to be demodulated as a reference for the APC circuit. The phase of the burst signal is compared with the phase of signal from a voltage controlled oscillator (which will be hereinafter referred simply to as a VCO). The phase of the signal from VCO is controlled by the compared error voltage. The VCO signal is frequency divided fed to a demodulator as a sub-carrier signal for demodulation.
APC circuits have a limited frequency range over which they can acquire and lock in the VCO signal. If the deviation of the frequency of the VCO exceeds the lock-in range of the APC circuit, APC operation is not performed. In the prior art, the VCO must be very stable using, for example, an expensive quartz crystal oscillator. APC circuits having wide lock-in range may be used, but such APC circuits generally require response times which are too long to be practical.